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Data Processing with Optimus

You're reading from   Data Processing with Optimus Supercharge big data preparation tasks for analytics and machine learning with Optimus using Dask and PySpark

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Product type Paperback
Published in Sep 2021
Publisher Packt
ISBN-13 9781801079563
Length 300 pages
Edition 1st Edition
Languages
Concepts
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Authors (2):
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Dr. Argenis Leon Dr. Argenis Leon
Author Profile Icon Dr. Argenis Leon
Dr. Argenis Leon
Luis Aguirre Contreras Luis Aguirre Contreras
Author Profile Icon Luis Aguirre Contreras
Luis Aguirre Contreras
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Table of Contents (16) Chapters Close

Preface 1. Section 1: Getting Started with Optimus
2. Chapter 1: Hi Optimus! FREE CHAPTER 3. Chapter 2: Data Loading, Saving, and File Formats 4. Section 2: Optimus – Transform and Rollout
5. Chapter 3: Data Wrangling 6. Chapter 4: Combining, Reshaping, and Aggregating Data 7. Chapter 5: Data Visualization and Profiling 8. Chapter 6: String Clustering 9. Chapter 7: Feature Engineering 10. Section 3: Advanced Features of Optimus
11. Chapter 8: Machine Learning 12. Chapter 9: Natural Language Processing 13. Chapter 10: Hacking Optimus 14. Chapter 11: Optimus as a Web Service 15. Other Books You May Enjoy

Handling missing values

One of the most common scenarios when handling data is to find missing values in your dataset.

Missing values are important to handle because, for example, many machine learning algorithms cannot have missing values if you want them to work properly. Or, if you are creating a report, you do not want to present stats with an aggregation of null values.

It's important to notice that Optimus treats None and NaN (Not a Number) values as interchangeable to indicate null values. To handle them, you can do two things: remove the data or impute it. In this section, we will present how Optimus can help with both tasks without providing an exhaustive statistical explanation of when to use each method. Let's see how Optimus can help us with both tasks.

Removing data

In this case, we will see how we can remove whole rows or columns that contain missing values.

Removing a row

First, let's create a dataframe with some null values in many...

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